Told to remove it, or holding a removal quote
Told to remove it: nothing measured made removal urgent, and there were signs of bats
Exeter · Recent inspection · Spray Foam Inspection
The house
Semi-detached house: concrete interlocking tiles on trussed rafters, blockwork gables. Of the roof vents fitted, only one is still open to the loft.
The foam
Open-cell, sprayed in 2022 and paid for privately. At numerous points it sits on an extra membrane laid over the original felt, its type unknown without a sample. Coverage is uneven: bare patches in places, about 75–100 mm beyond the rafters in others, and the eaves filled.
The paperwork
Installer's letter, payment receipt, a 25-year manufacturer's warranty and the product approval. Not provided: any record of the pre-installation inspection the approval requires, any thickness record, and any mention of the extra membrane. The warranty cites a different approval reference, and the installer has since ceased trading.
Why they called
The homeowner had been advised to have the foam removed, and wanted independent evidence before deciding.
What was measured
- 10 timber readings, all under 18%: highest 17.6% near the ridge, lowest 11.6%.
- Loft air 11.9 g/kg against 11.6 g/kg outside: a gap of +0.3 g/kg.
- Highest dew point 19.0 °C, coldest surface 19.4 °C on the north gable wall: a 0.4-degree margin on an early-autumn afternoon.
- Eaves 7.8 m each side, filled with foam at every point photographed, where guidance expects about 0.195 m² of opening per side.
- Floor insulation 50–100 mm deep, against 250 mm recorded on an earlier EPC.
What it means
Rot fungi do not normally establish in timber below about 20% moisture. Every reading here was under 18%, so nothing measured called for urgent removal. That is not a clean bill of health: with the eaves sealed and a 0.4-degree margin, water is likely to form at times in colder weather, and old drip marks suggest it has before.
What happened next
Heavy droppings, in the inspector's opinion from bats, put free bat advice first: bats and their roosts are protected, so it comes before any work in the loft. Then a roofer to check the tiles and clear foam from around the roof vents. Removal, if still wanted, only on like-for-like quotes planned around the bat advice.
For other homeowners
Before acting on advice to remove foam, ask what was measured. Here, ten readings under 18% bought time to act in the right order.
Read the guide: Do you need to remove spray foam? Removal, costs and what to check first · Spray foam cold calls and removal scams: how to check a caller
The honest limit
Timber behind the bonded foam and inside the filled eaves could not be seen or read. One afternoon visit; roof seen from the ground only.